1. Field of Invention
This invention relates to specialty marine tools and more particularly, to a lock tab wrench which is designed to remove lock tabs from the propeller shafts of outboard motors such as "Mercury" outboard motors and specifically, "Mercury" outboard motors using the "Mercury V-6 Chopper" propeller. The lock tab wrench of this invention is designed to engage, bend and straighten individual tabs which are radially spaced on a lock tab seated in the propeller hub on the motor shaft for engaging and securing a nut on the shaft and the propeller on the lower unit of the motor. In a preferred embodiment the lock tab wrench includes an elongated handle, a fulcrum projecting from the underside of the handle with a threaded allen screw seated in the fulcrum and a hook pivotally mounted on the end of the handle opposite the fulcrum. A retainer projects from the extending end of the hook for engaging and bending the respective tabs on the lock tab. The lock tab wrench is designed to bend individual tabs upwardly to straighten the tabs when it is desired to remove the lock tab and shaft nut from the propeller shaft in order to facilitate unthreading the shaft nut and the lock tab from the shaft to remove the propeller from the shaft.
One of the problems associated with the use of outboard motors, as well as outboard motor units of the inboard-outboard design, is that of losing propellers due to inadvertant unthreading of the shaft nut from the motor shaft. This problem frequently occurs when the shaft nut is not tightly secured on the shaft and sometimes under circumstances where the propeller is being removed while the boat is in the water. Since propellers are expensive operational parts of an outboard motor, many thousands of dollars are lost annually due to the accidental loosening and unthreading of shaft nuts from companion propeller shafts. The problem is intensified under circumstances where the motor under consideration is a high speed "Mercury" motor, and particularly those motors which are used for racing applications, where the engine revolutions per minute are very high. The problem is apparent not only in large motors but also in motors used for small pleasure boats, as well as those used in boats of intermediate size, such as those used for towing activities like water skiing.
One attempt to eliminate the problem of inadvertant loosening of the retaining nut or shaft nut on a propeller shaft with the resulting loss of a propeller, is that of using a lock tab which is fitted over the propeller shaft and receives the lock nut in a shaped receptacle to prevent the nut from unthreading on the shaft. These lock tabs are typically used on "Mercury" outboard motors and "Mercury" inboard-outboard drive systems which utilize the "Mercury V-6 Chopper" propeller, and are characterized by a round plate having a hexagonal-shaped receptacle stamped therein to receive the retainer nut and multiple, outwardly-extending and radially disposed tabs projecting from the plate. The tabs are designed to bend downwardly into slots provided in a lock tab seat located in the propeller hub when the propeller, lock tab and shaft nut are tightened in functional position on the propeller shaft. When the tabs are bent into the slots and the shaft nut is securely seated in the hexagonal cavity, the shaft nut is prevented from unthreading on the shaft. Accordingly, the tabs must be bent upwardly, out of the slots, in order to clear the lock tab seat and allow the shaft nut to be unthreaded from the shaft to effect removal of the propeller from the shaft and from the lower unit of the motor. The lock tab awrench of this invention is designed to perform this function.
2. Description of the Prior Art
There are various types of specialty wrenches designed for a variety of specific functions known in the art. Typical of these tools is the "C-Spanner or Wrench For Slotted Nuts or Parts" disclosed in U.S. Pat. No. 1,504,847, dated Aug. 12, 1924, to H. S. Tarr. This wrench is designed to engage slotted nuts or slotted circular bodies and is characterized by a stationary jaw, to one end of which is pivoted a movable jaw terminating in a hook. The hook is designed to engage the slot in a slotted nut or part, while the opposite edge or side of the slotted nut or part rests against the fixed jaw. The slotted nut or part is subjected to a torque when pressure is applied to the fixed jaw. In an alternative embodiment, the fixed jaw and movable jaw are connected by several links of a chain to facilitate engaging larger slotted nuts or parts. U.S. Pat. No. 1,707,856, dated Apr. 2, 1929, to H. Hoffman, discloses a "Wrench" which is characterized by a handle having a notched end that is received in and pivoted to a lug-receiving slot on one end of a curved jaw. The other end of the jaw is provided with an opening for receiving an opposite lug on the handle. A spring-influenced latch is engagable with the socket for locking the jaw to the handle when the wrench is in coupling-engaging position. An opposite movement of the latch permits swinging of the handle and jaw to bring the wrench out of engagement with the coupling. A "Spanner Ratchet Wrench" is disclosed in U.S. Pat. No. 2,373,210, dated Apr. 10,1945, to G. Van Genderen. The Van Genderen "Spanner Ratchet Wrench" includes an elongated rod and a pair of plates secured to opposite faces of the rod adjacent one end of the rod to form a channel therebetween, with the plates extending downwardly from the rod and each plate having a longitudinal slot provided in the downwardly extending portion thereof. The upper edge of the plate defining each slot is characterized by a series of ratchet teeth and a second elongated rod having one end located within the channel and a transverse pin projecting through the end of the rod within the channel, is provided for coaction with the ratchet teeth. A transverse pin secured to the opposite free end of each of the rods connects the rods to a hook-shaped member for engaging a workpiece to be manipulated. U.S. Pat. No. 3,148,567, dated Sept. 15, 1964, to J. D. Wood, discloses a "Forced Multiplication Device". The device of this invention includes a lever having a fixed arcuate jaw, multiple gripping projections provided along the inner surface of the fixed jaw, with each of the gripping projections having a redial surface and a cam surface, A pair of projecting lugs is provided on the lever and a movable arcuate jaw is pivotally mounted on the projecting lugs in opposed relationship with respect to the fixed arcuate jaw. Multiple gripping projections provided along the inner surface of the movable arcuate jaw feature radial surfaces and cam surfaces, respectfully. The movable jaw is of sufficient length to permit an end portion thereof to swing inwardly of the free end of the fixed jaw. A spring normally biases the movable jaw toward the fixed jaw and the manipulating boss on one end of the movable jaw facilitates opening of the jaws when force is applied thereto. U.S. Pat. No. 3,292,465, dated Dec. 20, 1966, discloses a "Tie Rod Spanner" which is characterized by a rigid elongated handle having a fixed jaw provided on one end, with a plurality of outwardly-projecting teeth provided around the periphery of the jaw, which teeth are located at a substantially uniform distance from an axis transverse to the jaw. A movable jaw is pivotally connected to the fixed jaw and is designed to swing about the transverse axis, with the movable jaw having work-engaging means provided on the free end thereof.
It is an object of this invention to provide a new and improved marine specialty tool for aiding in the removal of shaft nuts and propellers from the motor shafts of outboard motors and inboard-outboard motor drive systems which utilize lock tabs to secure the shaft nuts on the motor shafts.
Another object of this invention is to provide a lock tab wrench which is designed to bend and straighten the bent tabs on a lock tab which retains the shaft nut on the shaft of a motor, in order to facilitate removel of the shaft nut from the shaft.
Still another object of this invention is to provide a lock tab wrench which is characterized by an elongated handle, a fulcrum extending from the handle and a hook projecting from one end of the handle opposite the fulcrum for engaging the tabs in a lock tab and bending the tabs to straighten the tabs and facilitate removal of the retaining or shaft nut and the propeller from a motor shaft.
A further object of this invention is to provide a new and improved lock tab wrench which is characterized by a flat, elongated handle, a fulcrum extending from the handle, with threaded adjustment means located in the fulcrum, and a hook pivotedly attached to one end of the handle opposite the fulcrum, the hook designed to engage and straighten the tabs on a lock tab to facilitate unthreading a shaft nut from an outboard motor shaft in order to remove the propeller from the shaft.